The present invention relates to an energy absorbing apparatus for a vehicle body side portion, for, when a relatively large external shock is applied to a vehicle body side portion, absorbing the shock energy to protect passengers in a passenger room.
In recent years, the following proposal has been made. That is, a vehicle comprises energy absorbing bags, called air bags, which are normally set in a folded state. When a relatively large shock is applied to a vehicle body in a side collision state, the energy absorbing bag is quickly inflated, and the shock energy is absorbed by the inflated energy absorbing bag, thereby reducing the influence of the shock acting on passengers in a passenger room, and protecting the passengers.
In a vehicle having energy absorbing bags, for example, as disclosed in Japanese Utility Model Laid-Open No. 1-117957, a folded energy absorbing bag is stored in an armrest portion arranged on the passenger room side of a door forming a vehicle body side portion. The armrest portion also stores an inert gas generating agent, and an ignition device for causing the inert gas generating agent to generate the inert gas. Furthermore, a shock sensor for sensing a relatively large shock applied to a side sill is arranged in the side sill of the vehicle body, which is located under the door.
When the shock sensor generates a shock sensing output, the ignition device is operated in response to the sensing output, and causes the inert gas generating agent to generate the inert gas. The inert gas generated in this manner is quickly fed into the folded energy absorbing bag. As a result, the energy absorbing bag is inflated into the passenger room while breaking a thin portion formed in the armrest.
In this manner, in a vehicle having energy absorbing bags in vehicle body side portions, for example, when a shock caused by a side collision (a collision to a side portion of a given vehicle by, e.g., another vehicle) is applied to a vehicle body side portion, the energy absorbing bag is instantaneously inflated into the passenger room, and is interposed between the vehicle body side portion, e.g., a door, and a passenger seated inside the door. The shock energy caused by the shock applied to the vehicle body side portion is absorbed by the inflated energy absorbing bag, and a shock force acting sideways on the passenger can be reduced, thereby protecting the passenger.
In order to reduce a shock applied from the inflated energy absorbing bag to a passenger who collides against the inflated energy absorbing bag, the energy absorbing bag is normally formed with a plurality of degassing holes. Upon completion of inflation, the gas filled in the bag is degassed from the degassing holes, and the energy absorbing bag is immediately deflated.
A plurality of seats, i.e., front seats are normally aligned in the right-and-left direction, i.e., the widthwise direction of a vehicle body in a front portion in a passenger room of a conventional vehicle. In general, seat belts are equipped on the seats. It is desired in terms of safety that passengers who are seated on the front seats wear the seat belts, and the law states passengers must wear seat belts. However, in practice, passengers who are seated on the front seat do not always wear seat belts.
Therefore, a vehicle travels or is stopped under various different seating conditions of passengers on a plurality of seats arranged in the right-and-left direction in a passenger room, and various different use conditions of seat belts equipped on the seats.
For example, seating conditions of passengers, and use conditions of the seat belts of a driver's seat and a front passenger's seat arranged in the right-and-left direction in a front portion in a passenger room will be examined. In this case, the following eight conditions are possible:
1 Passengers are seated on both the driver's and front passenger's seats, and they both wear the seat belts. PA0 2 Passengers are seated on both the driver's and front passenger's seats, and only a driver on the driver's seat wears the seat belt. PA0 3 Passengers are seated on both the driver's and front passenger's seats, and only a passenger on the front passenger's seat wears the seat belt. PA0 4 Passengers are seated on both the driver's and front passenger's seats, and neither of them wear the seat belts. PA0 5 A person is seated on only the driver's seat, and he or she wears the seat belt. PA0 6 A person is seated on only the driver's seat, and he or she does not wear the seat belt. PA0 7 A passenger is seated on only the front passenger's seat, and he or she wears the seat belt. PA0 8 A passenger is seated on only the front passenger's seat, and he or she does not wear the seat belt.
Therefore, in the vehicle equipped with the energy absorbing bags, if the energy absorbing bag is quickly inflated, and is interposed between the vehicle body side portion and a passenger regardless of seating conditions of passengers in the passenger room, and use conditions of the seat belts when a shock caused by a side collision is applied to the vehicle body side portion, the energy absorbing bag which need not be inflated is undesirably inflated depending on seating conditions of passengers in the passenger room, and use conditions of the seat belts. Nitrogen gas degassed from the inflate energy absorbing bags via the degassing holes undesirably increases a nitrogen gas concentration in the passenger room, thus posing a problem.